Https://intercom.help/infanthelp/en/articles/11848644-can-you-add-a-baby-to-an-existing-allegiant-airlines-reservation-here-s-what-to-do https://intercom.help/infanthelp/en/articles/11848644-can-you-add-a-baby-to-an-existing-allegiant-airlines-reservation-here-s-what-to-do